Tailstock for lathes and like machinery



Dec'. 1, 1931. A. DRUMMOND TAILSTOCK FOR LATHES AND LIKE MACHINERY Filed June 1'7, 1929 2 Sheets-Sheet l & Q

l, 1931. DRUMMQND 1,834,831

TAILSTOCK FOR LATHES AND LIKE MACHINERY Filed June 17, 1929 2 Sheets-Sheet 2 Patented Dec. 1, 1931 PATENT OFFICE ARTHUR DRUMMOND, OF GUILDFORD, ENGLAND TAILSTOCK FOR LATHES AND LIKE MACHINERY Application filed June 17, 1929, Serial No. 371,663, and in Great Britain August 14, 1928.

This invention relates to tailstocks for lathes and like machinery such as grinders and milling machines (hereinafter referred to as lathes) and operating means therefor and is particularly applicable for use with metal working lathes adapted for mass production. In the ordinary form of lathe the time spent in setting up or removing the work in and from the lathe usually constitutes a small proportion of the time taken in the actualcutting operation which may occupy some hours. If, however, the lathe is adapted for mass production wherein, for example, the time taken in executing a similar cutting "operation occupies some minutes only, the time taken up in setting and removing the work such as manipulating the hand wheel of the tailstock and'the locking screw thereof assumes an important factor, and the present invention has for its chief object to reduce such time taken in effecting such necessary but non-productive operations.

According to the invention, in place of or' in addition to manual operating mechanism of the barrel of the tailstock, hydraulic operating means therefor are provided whereby, by the manual operation of, for example, a control cock or cocks, the said barrel is moved under fluid pressure towards or away from the work and as soon as the centre of the barrel and the work are in pressing contact the said barrel is locked a ainst further longitudinal movement in eit er direction by additional hydraulically controlled means. When the work has been completed further manipulation of the said control cock or cocks may be adapted to cause the barrel to be first unlocked and then retracted from the work 7 thereby permitting the latter to be removed 4 from the lathe. The pressure of the working fluid such as oil in order to effect such move ments of the barrel is preferably produced by a pump, carried by the lathe, which may be constantly driven by the main drive of the lathe so' that the tailstock can be operated when the lathe is at rest. According to one arrangement wherein the power is trans mitted to the lathe by a belt that, in known manner, is adapted to be moved laterally of the rims of fast and loose pulleys mounted about a common axis, the belt or a portion thereof is maintained in constant engagement with the rim of the loose pulley irrespective of its position relatively to the fast pulley and the said loose pulley is adapted constant ly to drive the pump of the hydraulic system. The building-up of the excessive pressure in the pipe lines for the working fluid is prevented by providing a relief valve which is arranged to permit the return of the working fluid to the sump when the pressure attains a predetermined value and in order to prevent a chattering or water hammering of the relief valve when it is caused to operate and which results in an intermittent or jerky movement of the part being moved as well as the liability of damage being caused to the lathe or to the system generally owing to the excessive and extensive vibrations so set up, a permanent leak or passageways may be provided between the suction and pressure sides of the pump so that at all times a portion of the working fluid is able to flow in a constant direction. The leak may be in the form of a by-pass around the relief valve and is preferably provided with a cock or tap for controlling the amount of fluid flowing through it.

In order that the said invention may be clearly understood and readily carried into so effect the same will now be described more fully with reference to the accompanying drawings illustrating preferred embodiments of the invention, and in which v Figure 1 is a sectional elevation of one form of tailstock the main body of which is adapted {)odbe fixed relatively to the lathe or other Figure 2 shows diagrammatically part of hydraulic operating means employed for effecting all the necessary movements of th tailstock, and, p

Figure 3 is a'diagrammatic sectional view of a further construction of tailstock.

Referring to Figure 1, 1 is the tailstock adapted to be fixed to the bed of a lathe and 2 a hollow cylindrical member positioned within the tailstock and capable of being adjusted longitudinally of the latter by means of a rack 3 and a pinion 4 which can be 0 Q forced forward untilthe centre 6 of thel J u r i i i fii' silient pressure ofthe coil spring-lil thereby manually actuated and the member locked in any desired position by a suitable clamping device (not shown). 5 is the barrel of the tailstock carrying a centre 6 and positioned concentrically within the member 2 by means of a clutch or clamping device 7 situated at the frontend of the barrel, thatis to say at the end thereof a jacent thework in the lathe, and by a bearing member 8 secured to the rear end of the member 2.

The hydraulic operatingmeans whereby thebarrel 5 can be moved relatively to the member 2 includes a cylin'd'er"9' positioned about the barrel 5 and capable of axialmovement within the member 2 and a double-act ingJpiston 10. secured a-medial position to; thebarrel 5 andprovided with cup washers 11;

of leather orother suitable material in contact,

-with theui'nnr cylindrical surface ofv the cylinder 9. The, cylinder-9 is provided with stuffing-boxes 12 andj13.at;its front andrear ends respectively thestutfing 100x12v being in] screwed ,engagement with, the clutch or.-

clampi151g'devifce 'z. A coilspring 14 isjposi;

iO 1ed between theinn r f ce-otthe eari g member 8 and the stuifing 130x313 so thatthe: cylinder '9, together with the. clutch or clamp:v ing device 'Z,;is constantly urged in adiree, tion towards. the work; Thebarrel 5- is, 7 formed withqtwo longitudinal passages 15 which-communicate by means of transverse passagesl6,- t h side flof h p ston 10. and, bymeans of slotsjl? formed in the rear end of the'ba-rr elf5, with further. passages 18 'formed in thebearing-member ,8 and com muni ated wi mu1tiWay. -Q r versi g. cook 19 carried by. the said, bearing member- 8. The cock 19 is in .coimnunication' with fluid; pressure, supply pipe 20 and I a release orexhaust pipe 2l'so that either end o-fthef cylinder Scan-be subjectedto the fluid pres,

sure or can; be connected directly to the re lease or exhaust pipe 21. The piston 10 may thus be forced towards either end of the cylinder 9 by actuation of the reversingcock 19 whereby the barrel 5 is moved towards. or awayfrorn the, work in the. lathe.

of a. split cone member 'or collet which engages with anappropriatelytapered orconed surface, 22 formed at the inner end of the cylindrical-member 2:530 that when the collet engages such tapered surface it is pressed inwardly to ;,eng ag e 'with' and lock the barrel 5.3 .Such' movement ofthe colletis eiiected in, the. following manner When' the end' of the cylinder 9, remote from the worlgis placedv in communication with the fluid pressure supply, the piston 10.and the barrel 5 are is'iin, pressing contact with the work.

ther, forward movement oi the barrel-g5 is; p vented, the. fluid pressure causes a reg: movement of the cylinder 9; against the causing a retraction of the collet and its movement into locking contact with the barrel 5 so that further longitudinal movement of the latter in either direction is prevented. By actuation of the reversing cook 19 the fluid under pressure can be admitted to the other side ofthe pistonlO whereupon thepressure offthe spring 14 causesftheforward longitudinal movement of the cylinder 9 with the con- "sequent displacement of the collet 7 relatively -to the-surface"22 0f-thebarrel 5 whereupon the piston 10 togetherwith the barrel is moved away'froni the "work'thereby releasing the centre .6.fr om contact with thelatter.

In Figure 2,28 is the pump, 'for'e-xample arota-ry gear pump, which supplies the fluid to themain pressure pipe20 ofthe hydraulic p raine mean I Th .bi i ge p e cessive pressure inthesystein isprevented by prov ding a relief valve. 25. which is ar{ ranged to perm t the sretiirn off the working tains. some predetermined value and inIorder a portionoi; the working fluid is ableto flow .in constant .direeti on. v The. transmission of power to the lathe and to the pump from a prime I rrover (notshownlliS fifie ctedby means of abelt 28 which canli be later ally movedlrelatively ,to the rims 6r fastand loose pulleys 29am} 30respectively mounted; about a. shaft. 31 which constitutes the 1 main drive shaft ot the Tlathejitselfa width of the. rim. of the loose pulley 29,, is substantially: that of the. belt 28 and is greater. than the width. of the rim of pulley 30' so that irrespective. of the position ofthe belt relatively to the fast pulley, the belt always overlaps and efifects a constant rotation of the loosepulley which is adapted to drive I v v the pump 23. by ,means of a. chain 32 and j The clutch; or clamping device 7 consist sv sprocket gwheelsjon the shaft of the pump :23

@Dil on the boss of the loose pulley 'or by. any other suitable power 1 transmission are sement v,+' =y n der.33 n mmu i ation with tl e plpes 20, 21 is mounted adjacent 'inder 33, thereby causing its piston to move.

ing in. the bElQbeing moved wholly oyer the under pressure from thesiunp .orfreservoir 24:

fluid to -thev sump when the pressure-at.

the, pulleys v29 ala r1130 and the lite 3.4; on f double actingv piston within the cylinder laterally offthe' 'rims of the pulleys. Bv

19 t] pulley29 for o ver the fast pulleyj and adjacentportionofthe loose pulley; ii A braki g. evi e fer-i s fia -1.13 1% iE J PQE towards onepf its extreme positions result- 1 vided in the formof a pivoted lever 38 which is normally out of contact with the fast pulley and which is adapted, when the belt is moved wholly over the loose pulley, to be v construction of tailstock, the centre 6 of the 7 ing barrel 5 is moved towards or away from the work by. means of a double-acting piston iO working within a hydraulic cylinder 41 and connected with the said barrel by rack teeth 42, 43 formed in thebarrel and piston respectively and engaging a common pinion wheel 14:. Both ends of the cylinder 41 are connected bymeans of pipe lines 45, 48 to the fluid pressure pipe 20and the exhaust or release pipe 21through the intermediary of a reversing cook or valve 47which can be actuated by rotation of the bevel gears 48 by a lever 49. It will be appreciated therefore that, dependent upon which end of the cylinder 41 is subjected to the fluid pressure, the barrel 5 can be moved either towards or away fromithe work by manipulation of the lever 49. I I V v If, for example, the barrel 5 is moved towards the work, the' centre 6 thereof is forced against the work at a pressure dependent upon the pressure of the fluid and the diameter of the piston 40. At this stage, fluid pressure is built lip-momentarily in the pipe line which effects the opening of a spring loaned valve/15 which admits the fluid into an additional cylinder 50 sim ilarly provided with a double-acting piston 51, and the latter is thus moved towards one of its extreme positions and causes a lock or clamping screw 52 to be operated by means of a rack 53 which is formed in or carried by the rod 54 of the piston 51 and which engages a pinion 55 associated with the clamping screw; such operation effecting the lockof the barrel 5 in its engaging position with the'work. Both ends of the cylinder 50 communicate with the reversing cook 47 by pipes 56, 57 so that, when it is desired to disengage the centre 6 from the work, the cock is manually operated causing the pressure end of the cylinder 50 to communicats with the exhaust or release pipe 21 and the other end thereof to communicate with the fluid pressure pipe 20 by the particular formation of passageways in the cock 4?, shown in dotted and dot and dash lines. The piston 5l is thereby moved in the reverse direction causing, in a manner as aforesaid, the locking screw 52 to be again operated to release the barrel for movement by the reverse motionof the piston 40 in the cylinder 1-1- consequent upon the reversal of the coir nectionsof the pipes 45,46 with the pressure in exhaustpipes 20, 21. v I

,The cylinders 41 and'50 and their component parts may be conveniently housed within the hollow casting of the tailstock itself and it is preferred to place the actuating handles of the various reversing cocks in such positions that any one of them can be readily actuated by, for example, the arm or elbow of the operator so that both hands of the latter are free to efiectthe setting up or removal of the work, or if desired any one or more of the said actuating handles may be extended downwardly or one or more of the said cocks may be so positioned that actuation thereof can be elfected by the foot of the operator. The hydraulic power produced by the pump 23 may be in excess of that required to actuate the tailstock and to control the rotation of themain driving shaft 31 and such excess power may be utilized in any desired manner, such as for example, in effecting the movements of the cutting tools of the lathe.

\Vhat I claim and desire to secure by Letters Patent of the United States is 1. Mechanism for operating a tailstork for lathes and other machine tools comprising a barrel in said tailstock, manually controlled hydraulically operated means for moving said barrel towards or away from the work in the machine tool, additional hydraulically operated locking means for preventing further longitudinal movement of the barrel in either direction when the said barrel is in pressing contact with the work, a sump containing working fluid, a pump for supplying the working fluid under pressure from the sump to the said hydraulically operated means, a power drive for said machine tool and means associated with the said power drive for constantly driving the said pump;

2. Mechanism for operating a tailstock for lathes and other machine tools comprising a barrel'in said tailstock, manually controlled hydraulically operated means for moving said barrel towards or away from the work in the machine tool, additional hydraulically operated locking means for preventing further longitudinal movement of the barrel in either direction when the said barrel is in pressing contact with the work, a sump containing working fluid, a pump for supplying the working fluid under pressure from the sump to the said hydraulically operated means, a counter-shaft, a fast pulley secured to said counter-shaft, a loose pulley mounted on the shaft adjacent the fast pulley, a power transmission belt constantly in engagement with the said loose pulley and means associated with the said loose pulley for driving the pump.

3. Mechanism for operating a tailstock for lathes and other machine tools comprising a barrel in said tailstock, manually controlled hydraulically operated means for moving said barrel towards or away from the work in the machine tool, additional hydraulically operated locking means for preventing furplying: the working fluid under pressure from.

the sump. to the saidhydraulicallyoperated means, a counter-shaft, a fast pulley secured to said counter-shaft, a loose pulley mounted on the counter-shaft adjacent the fast pulley,

' a power tr nsmission belt constantly in on gagement with the said loose pulley,- a. hy-

draulically operated device, for moving the belt laterally acrossthe rims-of the fast; and loose: pulleys, and,,means'. for driving the pump associated with the said loose pulley, ,Mechanism for operating av tailstock for;

lathes and other machine toolscomprising barrel in saidtailstoclr, manually controlled.

hydraulic-ally operated means for moving said barrel; towards. or. away from the work in;

the machine tool, additional hydraulically operated locking means. for preventingfurther longitudinal movement of the barrel in eitherdirection when the said'barrel is in press ng contact with the work, a sumpg'con;

taining working fluid, a pump forsupplying the working fluid under pressure from. the. sump. to the said, hydraulically operated means, arelief valve to return the working fluid from the-pumpto the said sump, a coun tor-shaft, a fast pulley secured to said ,coiinter-shaft,,ja loose pulley mounted on, the

7 pulley mounted on the counter-shaft .adja

counter-shaft adjacent the fast pulley, az pow or transmission belt, constantly in engage ment with the said loose pulley, a hydraulically operated device for moving. the belt latery ally across the rims of the fast and loosepul leys, and means associated with the said. loose pulley for driving; the pump.

5. Mechanism for operatinga tailstockifor;

latlies and other machine tools comprising a barrel in said tallstock, manually controlled hydraulically operated means for movingsaidbarrel towards or away from the work' "1, in themachine tool, additional hydraulically operated locking means. for preventing. fur-.

ther longitudinal movement of the barrel either direction when the said barrel in pressing contact with the I work, I a sump con:

taining working iflui a pumpfor supply-1 ing the working fluid. under pressure from, the sump to: the said hydraulically operated n1eans,a relief valvev to returntheworking fluidfrointhe pump to the saidsump, aby-v iass positioned between the suctionand press sure sides of the p-ump ,a counter-shaft,a fast pulley secured to said counter-shaft, a, loose cent the fast pulley, a power transmission belt 2 constantly in engagement withthesaid loose pulley, a hydraulically operated devlce for, moving the belt laterallyacross the rims-of the fast and loosepull eys, and means fo-r.driv-.

ing the pump associated with the said loose;

pulley.

61;.Mecha-nism for operatinga tailstocli' for lathes andwo'ther machine-tools comprising a barrel in said t'ailstock, manually controlled hydraulically operated meansformoving said.

barrel; towards or away. from the. work in the machine tool-,- additional hydraulically oper-. ated locking'means for: preventing further longitudinal movement, of the barrel .in either direction when the said barrel is. in. pressing contact with the work, av sump.- con-- taining working fluid, a-p-ump for supplylng the working fluid. under pressure from the sump to the said hydraulically operated means, a reliefvalve'to return the working fluid fromthe. pump. to thecsaid-sump, a, bypass positioned between the'suction and pres? sure sides ofthepump: andpmeans for con? trolling the amountofworking' fiuid passing throughsaid Joy-pass, a power drive for said machinetool and'means associated WllillSllCl' power drive for constantly driving the said pumpj pmm 1, i

7.; A tailstockiforlathes. and' other. machine tools comprising a memberlongitudinally adjustable; within said ,tailstock, a clamping devicepo'sitioned at thefr-ont end of said member, a bearing element secured to 'the rear enduofsaid member, abarrel sl'idably mounted inusaidclampjing device and said. bearing element, a cylinder positioned about said barrel andsecurcd to, said clamping vdc vice, a piston carried Jbysaid barrel and positioned. within :the gcylinden-aspring in-v serted between the reariendiof the cylinder and'thc said bearing-element and manually controlled means for admitting fluid under pressure to eitherend of the cylinder;

A tailst-ock forlathes and othermachine tools comprising a;memberlongitudinally adjustable within said tailstock, i part-conical surface formedat-the frontend of the adjustablemember,a collet adapted to engage saidsurface ancl positioned at the front end of saidmembenxa bearing element secured to the. rear end 'of said member, a barrel slidablymo-unted in Said collet and saidbearing element, a cylinder positioned about said barrel andsecuredto sa'idcollet, a piston carriedby said barrel and positionedwithin the cylinder, spring. inserted between the rear end of the cylinderyarid'thc Said bearingelement and manually controlled means for admittingfluid under pressure to either end of the-cylindenf a, I I 9.- A; tailstoclr for lathes and other machine toolsf comprising; a member longitudinaillyadju-stable within SQLl Cl'ltallStOCk, a clamping device positioned at the front end of said member, a-bearingelemcnt secured "to-the. rearend-of saidmember, a, barrel slidabl'y inounted in said; clamping device and said bearing element, a cylinder positioned abc-u-tsaid barreland securedto said. clamping device, a piston carried. bysaid barrel and positioned vwithinj' the cylinder; a. spring inserted between the rear end of the cylinder and the said bearing element, a manually operated reversing cock, a fluid pressure pipe communicating with said cock, an exhaust pipe communicating with said cock and passageways communicating between said cock and both ends of the said cylinder, and manually controlled means for admitting fluid under pressure to either end of the cylinder.

10. A tailstock for lathes and other machine tools comprising a center holder, locking means for locking said centre holder against longitudinal movement, a cylinder the end Walls of which are capable of longitudinal movement, inopposite directions and one of which walls is connected to said holder and the other to means for operating said locking means, yielding means tending to maintain said locking means inoperative, and means for supplying fluid under pressure to said cylinder between said end walls.

11. Atailstock for lathes and other machine tools comprising a centre holder, a cylinder having end walls, a piston located within said cylinder and connected to said holder, locking means for locking said holder against longitudinal movement connected to said cylinder andoperable thereby, yielding means normally to maintain said cylinder from movement in the direction away from the work, and hand controlled means for supplying fluid pressure to said cylinder on either side of said piston.

12. A tailstock for lathes and other machine tools comprising a member longitudinally adjustable within said tailstock, a barrel, a centre carried by said barrel, means for positioning the barrel concentrically within said member consisting of a clamping device positioned at the front end of said member and a bearing element secured to the rear end of said member, manually controlled hydraulically operated means for moving said barrel towards or away from the work in the machine tool and additional hydraulically operated locking means for preventing further longitudinal movement of the barrel in either direction when the centre is in pressing contact with the work the first mentioned hydraulically operated means including a cylinder positioned about the barrel and adapted to be moved within the adjustable member and a double acting piston secured to the barrel and positioned within the cylinder.

13. A tailstock for lathes and other nia chine tools comprising a centre holder. a movable member connected to said holder, locking means for locking said holder against longitudinal movement, a movable member connected to said locking means, a fluid pressure supply arranged for operating both said members, and means to prevent operation of the locking means until the first mentioned member has been moved by the fluid pressure to bring the centre into contact with the work whereafter the fluid pressure operates the second mentioned member to move said locking means into the locking position.

14. A tailstock for lathes and other machine tools comprising a centre holder, a cyl inder, a piston in said cylinder and connected to said holder, locking means for locking said holder against longitudinal movement, a second cylinder, a piston in said second cylinder connected with said locking means, a fluid pressure supply conduit connected with both cylinders, and a pressure operated valve adapted to prevent entrance of fluid pressure to the second cylinder.

15. A tailstock for lathes and other machine tools comprising a centre holder, means to move said holder into contact with the work, means to lock the holder against longitudinal movement when the centre is in contact with the work, and hydraulically operating means which when put in operation act automatically first to unlock said means and then to move said holder away from the work.

16. A tailstoek for lathes and other machine tools comprising a center holder, hydraulically operated means for moving said holder towards the work, locking means for locking said holder against longitudinal movement, a spring normally preventing operation of said locking means, and a hand con trolled device for supplying fluid pressure to both said means.

17. A tailstock for lathes and other machine tools comprising a center holder, hydraulically operating means including a piston device for moving said holder towards the work, other hydraulicaly operated means including a second. piston device for locking the holder against longitudinal movement, yielding means tending to prevent operation of the locking means, and a hand controlled valve for supplying fluid to both said piston devices.

18. A tailstock for lathes and other machine tools comprising a center holder, means to move the holder towards the work, a clamping device for preventing longitudinal movement of the holder, means to operate said device, a spring tending to prevent operation of the clamping device, a hydraulic arrangement for operating both said means including fluid pressure communication between said means, the arrangement being such that the fluid pressure operates between said means first in one direction to actuate the means for moving the holder into engagement with the work whereafter the pressure acts in the opposite direction to overcome the resistance of the spring and operate the locking means.

ARTHUR DRUMMOND. 

